1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method, and more particularly, to those for detecting and processing a change in image.
2. Description of Related Art
Heretofore, an image processing system for detecting the presence of a moving body on the basis of a change in image by an image processing method called a background difference technique has been developed and put into practical use.
In brief, according to the background difference technique, a difference between a background image prepared from an image previously picked up with a camera and image information newly picked up with the camera is detected as a moving body. In such detection of a moving body, it is general that, in order to cope with changes in lightness of a scene under surveillance or observation (an object of shooting), a background image is updated on the basis of the picked-up image information.
Responses obtainable by the background difference technique include a response caused by the presence of a moving body and a response caused by a change in lightness of a scene under surveillance or observation. In the case of the former response, giving a notice of the presence of the moving body is necessary. In the case of the latter response, the background image is required to be updated.
However, according to the prior art, it is necessary to make a discrimination between the two different responses solely on the basis of image information. The prior art method, therefore, necessitates a complex image processing operation. Besides, since it is difficult to accurately distinguish the two different responses from each other, the detection of a moving body is made leaving some ambiguity, which deteriorates the accuracy of detection.
The invention is directed to the solution of the above-stated problem of the prior art. It is, therefore, an object of the invention to provide an image processing apparatus which is capable of more accurately detecting a moving body by clearly discriminating between a response caused by the presence of the moving body and a response caused by a change in lightness of a scene under surveillance or observation.
To attain the above object, in accordance with an aspect of the invention, an image processing apparatus or an image processing method is arranged to input image data obtained by image pickup means and an image pickup parameter of the image pickup means used in obtaining the image data, to make a comparison between the image pickup parameter for a target image and the image pickup parameter for another image, and to decide whether or not the target image differs from the other image, according to a result of the comparison.
Further, in accordance with another aspect of the invention, an image processing apparatus or an image processing method is arranged to measure an optical parameter, to generate image data while controlling an optical system according to a result of the measurement, to store the measured optical parameter in a storage medium, to make a comparison between the measured optical parameter and the optical parameter stored in the storage medium, and to decide any change in the image data according to a result of the comparison.
The above and other objects, features and advantages of the invention will become apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings.